JP6513834B2 - Method and apparatus for improving LTE-WLAN coordination in a wireless communication system - Google Patents

Description

  The present invention relates to wireless communication, and more particularly, to a method and apparatus for improving coordination of 3rd generation partnership project (3GPP) long-term evolution (LTE) and wireless local area network (WLAN) in a wireless communication system. .

  3GPP LTE is a technology for enabling high-speed packet communication. Many schemes have been proposed for cost reduction of users and operators, quality of service improvement, coverage extension and system capacity increase, which are LTE targets. 3GPP LTE requires cost savings per bit, improved service availability, flexible use of frequency bands, simple structure, open interfaces and proper power consumption of terminals as high-level requirements.

  Since Rel-8, 3GPP has standardized access network discovery and selection functions (ANDSF) for interworking between 3GPP connected networks and non-3GPP connected networks (e.g. WLAN (wireless local area network)). Are connected network detection information (eg, WLAN, WiMAX location information, etc.) connectable at the UE (user equipment) location, inter-system mobility policies (ISMP) that can reflect the operator's policy, and ISRP It can carry an (inter-system routing policy), based on the above information, the UE can decide if certain IP (Internet protocol) traffic is sent over a connected network. The UE has one activated connection network connection (eg, WLAN or Or a network selection rule for selecting 3GPP) ISRP is a network selection rule for the UE to select one or more possible activated connection network connections (WLAN and 3GPP all) ISRP can include MAPCON (multiple access connectivity), IFOM (IP flow mobility), and non-seamless WLAN offloading, dynamic between ANDSF and UE OMA (open mobile alliance) DM (device management) can be used for provisioning.

  WLAN interworking and integration are currently supported at the CN level by 3GPP standard documents, which include both seamless and non-continuous mobility to WLAN. 3GPP has agreed to study possible RAN level enhancements for WLAN / 3GPP interworking in Rel-12. In particular, in addition to ANDSF, a policy, namely radio access network (RAN) rules, has been specified in Rel-12 due to the link between 3GPP access networks and non-3GPP access networks (e.g. WLAN). This policy may support access network selection and traffic coordination between LTE and WLAN.

  The LTE and WLAN interworking is gradually moving towards integrating LTE and WLAN. As a result, not only LTE-WLAN interworking has been improved, but LTE-WLAN aggregation has recently been studied.

  The present invention provides a method and apparatus for improving the coordination of 3rd generation partnership project (3GPP) long-term evolution (LTE) and wireless local area network (WLAN) in a wireless communication system. The present invention provides a method and apparatus for assisting an eNB (eNodeB) to decide to off-node bearer from LTE to WLAN or from WLAN to LTE.

  In one aspect, a method is provided for transmitting an indication for coordination of a 3rd generation partnership project (3GPP) long-term evolution (LTE) and a wireless local area network (WLAN) by an eNB (eNodeB) in a wireless communication system. The method includes transmitting a first indication of WLAN offloading support to a mobility management entity (MME) and receiving a second indication from the eNB applying a different charging rule.

  In another aspect, a method is provided for transmitting an indication for coordination of a 3rd generation partnership project (3GPP) long-term evolution (LTE) and wireless local area network (WLAN) by an eNB (eNodeB) in a wireless communication system . The method may send a first indication of WLAN offloading support to a mobility management entity (MME), a second indication of whether a bearer may be offloaded from the MME, and the second indication And applying offloading to a specific terminal (UE; user equipment) according to.

  3GPP / WLAN coordination may be improved.

1 shows the structure of an LTE system. FIG. 1 shows a block diagram of the structure of a generic E-UTRAN and EPC. FIG. 7 shows a block diagram of a user plane protocol stack of an LTE system. FIG. 7 shows a block diagram of a control plane protocol stack of an LTE system. An example of a physical channel structure is shown. 7 shows an example of an architecture for LTE / WLAN coordination. 7 illustrates a method for transmitting an indication for LTE / WLAN coordination according to an embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. 1 illustrates a wireless communication system in which an embodiment of the present invention is implemented.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division access (SC-FDMA), and the like. May be used in various wireless communication systems such as CDMA can be realized by a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA can be realized by a radio technology such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for advanced transmission (EDGE). OFDMA is to be realized by a wireless technology such as IEEE (institute of electrical and electronics engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA (evolved UTRA), etc. Can. IEEE 802.16m is an evolution of IEEE 802.16e and provides backwards compatibility with IEEE 802.16 based systems. UTRA is part of the universal mobile telecommunications system (UMTS). 3GPP (3 ^rd generation partnership project) LTE (long term evolution) is part of E-UMTS (evolved UMTS) using E-UTRA (evolved-UMTS terrestrial radio access) and employs OFDMA in the downlink , SC-FDMA on the uplink. LTE-A (advanced) is an evolution of 3GPP LTE.

  In order to clarify the description, the description will be made focusing on LTE-A, but the technical idea of the present invention is not limited thereto.

  FIG. 1 shows the structure of the LTE system. Communication networks are widely installed to provide various communication services such as IMS and Voice over Internet Protocol (VoIP) via packet data.

  As shown in FIG. 1, the LTE system structure includes one or more terminals (UEs) 10, an E-UTRAN (evolved-UMTS terrestrial radio access network), and an EPC (evolved packet core). The terminal 10 is a communication device operated by a user. The terminal 10 may be fixed or mobile, and may be in other terms such as MS (mobile station), UT (user terminal), SS (subscriber station), wireless device (wireless device), etc. Sometimes called.

  The E-UTRAN includes one or more eNBs (evolved node-B) 20, and a plurality of UEs can exist in one cell. The eNB 20 provides the UE with a termination point of a control plane and a user plane. The eNB 20 generally refers to a fixed station that communicates with the UE 10, and may be referred to in other terms such as a base station (BS), an access point, and the like. One eNB 20 can be deployed per cell.

  Hereinafter, DL means communication from eNB 20 to UE 10, and UL means communication from UE 10 to eNB 20. In DL, the transmitter may be part of eNB 20 and the receiver may be part of UE 10. In UL, the transmitter may be part of UE 10 and the receiver may be part of eNB 20.

  The EPC includes an MME (mobility management entity) and an S-GW (serving gateway). The MME / S-GW 30 can be located at the end of the network. For the sake of clarity, MME / S-GW 30 is simply referred to herein as "gateway", but such individuals are understood as including MME and S-GW. PDN (Packet Data Network) Gateway (P-GW) can be connected to an external network.

  MME performs non-access stratum (NAS) signaling to eNB 20, NAS signaling security, access stratum (AS) security control, inter network (core network) node signaling for mobility between 3GPP access networks, idle mode terminal reachability (Including control and execution of paging retransmission), tracking area list management (for UE in idle mode and activation mode), P-GW (PDN (packet data network) gateway) and S-GW selection, MME MME selection for handover with change, SGSN (serving GPRS support node) selection for handover to 2G or 3G 3GPP access network, roaming, authentication, bearer management function including dedicated bearer configuration, PWS (public warning system: Earthquake / tsunami warning system (ETW S) and provide various functions such as support for mobile alarm system (CMAS) message transmission support. The S-GW host performs per-user based packet filtering (eg through deep layer packet inspection), lawful blocking, internet protocol (IP) address assignment, transmission level packing marking in DL, UL / DL service level charging, gating and It provides various functions of DL enforcement according to the grade enforcement, APN-AMBR (access point name aggregate maximum bit rate).

  An interface for user traffic transmission or control traffic transmission can be used. The UE 10 and the eNB 20 are connected by the Uu interface. The eNBs 20 are mutually connected by an X2 interface. Adjacent eNBs 20 may have a network network structure with an X2 interface. A plurality of nodes can be connected between the eNB 20 and the gateway 30 via an S1 interface.

  FIG. 2 is a block diagram of the general E-UTRAN and EPC structure. As shown in FIG. 2, the eNB 20 performs selection on the gateway 30, routing to the gateway 30 during radio resource control (RRC) activation, scheduling and transmission of a paging message, and scheduling of broadcast channel (BCH) information. And transmission, dynamic allocation of resources from UL and DL to UE 10, configuration and provision of eNB measurement, radio bearer control, radio admission control (RAC) and connectivity mobility control function in LTE active state It can be done. As described above, the gateway 30 can perform paging start, LTE idle state management, user plane encryption, SAE bearer control, NAS signaling encryption and integrity protection functions with EPC.

  FIG. 3 is a block diagram of a user plane protocol stack of the LTE system. FIG. 4 is a block diagram of a control plane protocol stack of the LTE system. The layer of the radio interface protocol between the UE and the E-UTRAN is L1 (layer 1), L2 (layer 2) based on the lower three layers of the open system interconnection (OSI) model widely known in communication systems. , And L3 (third hierarchy).

  The physical layer (PHY; physical layer) belongs to L1. The physical layer provides an upper layer with an information transmission service via a physical channel. The physical layer is connected to a media access control (MAC) layer, which is an upper layer, via a transport channel. Physical channels are mapped to transmission channels. Data is transmitted between the MAC layer and the physical layer via the transmission channel. Data are transmitted via physical channels between different physical layers, ie between the physical layer of the transmitter and the physical layer of the receiver.

  The MAC layer, the RLC (radio link control) layer, and the PDCP (packet data convergence protocol) layer belong to L2. The MAC layer provides services to the RLC layer, which is the upper layer, through a logical channel. The MAC layer provides data transmission services on logical channels. The RLC layer supports reliable data transmission. On the other hand, the functions of the RLC layer can be realized by functional blocks within the MAC layer, and in this case, the RLC layer may not exist. The PDCP layer provides header compression that reduces unnecessary control information so that data sent using IP packets such as IPv4 or IPv6 can be efficiently transmitted on relatively small bandwidth wireless interfaces Do.

  A radio resource control (RRC) layer belongs to L3. The RRC layer located at the lowermost part of L3 is defined only by the control plane. The RRC layer is responsible for control of logical channels, transmission channels, physical channels and the like in association with configuration (configuration) such as radio bearer (RB), reconfiguration (configuration), and release (release). RB means the service provided by L2 for data transmission between UE and E-UTRAN.

  As shown in FIG. 3, the RLC and MAC layers (terminating at eNB on the network side) may perform functions such as scheduling, ARQ and HARQ. The PDCP layer (terminating at eNB on the network side) can perform user plane functions such as header compression, integrity protection, and encryption.

  As shown in FIG. 4, the RLC / MAC layer (terminated at eNB on the network side) can perform the same function for the control plane. The RRC layer (terminated at eNB on the network side) may perform functions such as broadcasting, paging, RRC connection management, RB control, mobility function, and UE measurement reporting and control. The NAS control protocol (terminating on the MME at the gateway on the network side) performs functions such as SAE bearer management, authentication, LTE_IDLE mobility management, paging initiation in LTE_IDLE, and security control for signaling between gateway and UE can do.

  FIG. 5 shows an example of a physical channel structure. The physical channel transmits signaling and data between the UE physical layer and the eNB physical layer through radio resources. A physical channel is composed of a plurality of subframes in the time domain and a plurality of subcarriers in the frequency domain. One subframe, which is 1 ms, is composed of a plurality of symbols in the time domain. A specific symbol of the corresponding subframe, eg, a first symbol of the subframe, may be used for PDCCH. The PDCCH may carry dynamically allocated resources such as physical resource blocks (PRBs) and modulation and coding schemes (MCSs).

  The DL transmission channel is a BCH (broadcast channel) used to transmit system information, a PCH (paging channel) used to page a UE, DL used to transmit user traffic or control signals. And includes a downlink shared channel (SCH), a multicast channel (MCH) used for multicast or b-node cast service transmission, and the like. The DL-SCH supports dynamic link adaptation and dynamic / semi-static resource allocation with HARQ, modulation, coding and transmission power change. Also, DL-SCH can enable the use of broadcast and beamforming throughout the cell.

  The UL transmission channel may be a random access channel (RACH) generally used for initial connection to a cell, user traffic, or a UL-SCH (uplink shared channel) used to transmit control signals, etc. Including. UL-SCH supports dynamic link adaptation with HARQ and transmission power and potential modulation and coding changes. Also, UL-SCH can enable the use of beamforming.

  Logical channels are classified into control channels for control plane signaling and traffic channels for user plane signaling according to the type of information to be transmitted. That is, a set of logical channel types is defined for different data transmission services provided by the MAC layer.

  Control channels are used for control plane signaling only. Control channels provided by the MAC layer include a broadcast control channel (BCCH), a paging control channel (PCCH), a common control channel (CCCH), a multicast control channel (MCCH), and a dedicated control channel (DCCH). BCCH is a DL channel for broadcasting system control information. The PCCH is a DL channel for transmitting paging information, and is used when the network does not know the location of the UE on a cell basis. The CCCH is used by the UE when it has no RRC connection with the network. The MCCH is a point-to-multipoint DL channel used to transmit MBMS (multimedia broadcast multicast services) control information from the network to the UE. The DCCH is a one-to-one bi-directional channel used by UEs having an RRC connection for dedicated control information transmission between the UEs and the network.

  The traffic channel is used only for user plane communication. The traffic channels provided by the MAC layer include a dedicated traffic channel (DTCH) and a multicast traffic channel (MTCH). The DTCH is a one-to-one channel, used for transmission of user information of one UE, and can be present in all UL and DL. The MTCH is a point-to-multipoint DL channel for transmitting traffic data from the network to the UE.

  The UL concatenation between the logical channel and the transmission channel includes DCCH, which can be mapped to UL-SCH, DTCH, which can be mapped to UL-SCH, and CCCH, which can be mapped to UL-SCH. The DL connection between the logical channel and the transmission channel can be mapped to BCH or DL-SCH, BCCH mapped to PCH, PCCH mapped to PCH, DCCH mapped to DL-SCH, DTCH mapped to DL-SCH, MCCH mapped to MCH And MTCH which can be mapped to MCH.

  The RRC state indicates whether the UE's RRC layer is logically connected to the E-UTRAN RRC layer. The RRC state is divided into two types such as RRC connected state (RRC_CONNECTED) and RRC idle state (RRC_IDLE). In RRC_IDLE, the UE can receive broadcasts of system information and paging information while the UE designates DRX (discontinuous reception) configured by the NAS. Then, the UE may perform public land mobile network (PLMN) selection and cell reselection based on assignment of an ID (identification) uniquely specifying the UE in the tracking area. Also, in RRC_IDLE, no RRC context is stored in eNB.

  With RRC_CONNECTED, the UE may have an E-UTRAN RRC connection and context in E-UTRAN to send data to and / or receive data from the eNB. Also, the UE can report channel quality information and feedback information to the eNB. With RRC_CONNECTED, the E-UTRAN can know the cell to which the UE belongs. Thus, the network can send data to the UE and / or receive data from the UE, and the network can be in the mobility of the UE (in GSM EDGE radio access network (GERAN) through handover and network assisted cell change (NACC)). An inter-RAT (radio access technology) cell change indication can be controlled, and the network can perform cell measurements for neighboring cells.

  In RRC_IDLE, UE specifies a paging DRX cycle. Specifically, the UE monitors the paging signal at a specific paging occasion per UE specific paging DRX cycle. A paging occasion is a time interval during which a paging signal is transmitted. The UE has its own paging occasions. A paging message is sent above all cells belonging to the same tracking area (TA). If the UE moves from one TA to another, the UE can send a TAU (tracking area update) message to the network to update its location.

  The 3GPP / WLAN wireless interworking Release-12 solution can improve the core network infrastructure WLAN off-node by improving the quality of experience (QoE) and network utilization and providing the operator with more control. Such enhancements can be most enhanced by LTE-WLAN integration and further LTE / WLAN interworking enhancement related to all co-located and non-co-located deployment scenarios.

  The advantages of LTE / WLAN integration are as follows.

  (1) The WLAN connection network is transparent to the CN in that it should not require a WLAN-specific CN node and a CN interface. This provides the operator with all these integrated control and management as opposed to managing 3GPP and WLAN networks individually.

  (2) Integration and tight integration at the radio level to provide substantial capacity and QoE improvement enables real-time channel and node aware radio resource management via WLAN and LTE.

  (3) An LTE network that can be trusted as a control and mobility anchor can be used to provide QoE improvement, minimize service interruption, and increase operator control.

  (4) Degenerate CN nodes as new WLAN-associated CN signaling is not required.

  The advantages of LTE / WLAN assembly can be realized with both co-located and non-co-location. In the case of a common location that corresponds to a small cell deployment, the LTE eNB and the WLAN AP are physically integrated and connected via an internal interface. Such a scenario is similar to LTE carrier aggregation. In the case of non-common location, LTE eNB and WLAN are connected via an external interface. Such a scenario is similar to LTE double concatenation. The control is managed by the eNB via RRC whereas the WLAN link operates on the second connection for data, both in the case of co-location and non- co-location.

  FIG. 6 shows an example of an architecture for LTE / WLAN coordination. The architecture shown in FIG. 6 corresponds to the case of co-location. As shown in FIG. 6, the eNB is co-located with the WLAN AP. Alternatively, the eNB may be connected to the WLAN by an interface. Also, the UE may be co-located with a WLAN station (STA). The eNB is connected to the eNB via an E-UTRA Uu interface, and the WLAN STA is connected to the WLAN AP via Wi-Fi. In such case, LTE and WLAN traffic may be sent to the core network via the eNB. That is, WLAN traffic can be managed by LTE.

  If the architecture for LTE / WLAN coordination presented above is used for LTE / WLAN aggregation / interworking, then the eNB decides to off-node bearer from LTE to WLAN or from WLAN to LTE Can be a problem. Also, the way in which the core network recognizes whether a particular UE is served by WLAN can be problematic.

  In order to solve the above mentioned problems, a method is proposed to improve 3GPP / WLAN coordination. According to one embodiment of the present invention, a method is proposed to help the eNB decide to offload bearers from LTE to WLAN or from WLAN to LTE. According to another embodiment of the present invention, a method is proposed to inform the core network whether a specific UE is served by WLAN.

  First, a method for transmitting an indication for LTE / WLAN coordination is described to assist an eNB to decide to offload a bearer according to an embodiment of the present invention.

  FIG. 7 illustrates a method for transmitting an indication for LTE / WLAN coordination according to an embodiment of the present invention. The method shown in FIG. 7 corresponds to a cell-specific scheme. That is, the method illustrated in FIG. 7 may be applied to all UEs linked to an eNB.

  In step S100, the eNB transmits a first instruction of WLAN offloading support to the MME. The first instruction indicates whether the eNB supports WLAN offloading. The first instruction may be sent via an S1 setup request message during an S1 setup procedure, or may be sent via an eNB configuration update message after the S1 setup is completed. However, the S1 configuration request message or the eNB configuration update message is merely exemplary, and the first indication may be sent via another existing message or a newly defined message for such purpose. Can. Also, a WLAN ID (e.g., an SSID (service set ID)) may be transmitted to the MME along with the first indication of the WLAN offloading support.

  In step S101, the MME transmits, to the eNB, a second instruction to apply different charging rules. The second indication indicates that the eNB needs to report to the MME regarding the specific bearer offloading state for each UE. The second instruction information is transmitted during the S1 setup procedure as a response to the S1 setup request message via the S1 setup response message or after the S1 setup is completed, the eNB configuration as a response to the eNB configuration update message It may be sent via an update acknowledgment message. However, the S1 configuration response message or the eNB configuration update acknowledgment message is merely an example, and the second indication is sent via another existing message or a newly defined message for such purpose. Can be

  FIG. 8 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 8 corresponds to an example of the method shown in FIG. 7, which is implemented by the S1 setup request / response message during the S1 setup procedure.

  In step S110, the eNB transmits an S1 configuration request message to the MME. The S1 setup request message is used to transmit information for transport network layer (TNL) association. Tables 1 and 2 illustrate an example of an S1 setup request message according to an embodiment of the present invention.

<Table 1>

<Table 2>

  Referring to Table 1, the S1 setup request message may include an "indication of WLAN offloading support" field, which corresponds to the first indication shown in FIG. Also, the S1 setup request message may include a "List of WLAN" field.

  In step S111, the MME transmits an S1 setting response message to the eNB. The S1 setup response message is used to transmit information for TNL association. Tables 3 and 4 illustrate an example of an S1 setup response message according to an embodiment of the present invention.

＜表３−２＞

<Table 3-1>

<Table 3-2>

<Table 4>

  Referring to Table 3, the S1 configuration response message may include a "with indication of applying different charging rule" field, which corresponds to the second indication shown in FIG.

  FIG. 9 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 9 corresponds to an example of the method shown in FIG. 7, which is implemented by the eNB configuration update / acknowledgement message during the eNB configuration update procedure.

  In step S120, the eNB transmits an eNB configuration update message to the MME. The eNB configuration update message is used to convey updated information for TNL association. Tables 5 and 6 illustrate examples of eNB configuration update messages according to an embodiment of the present invention.

<Table 5>

<Table 6>

  Referring to Table 5, the eNB configuration update message may include an "indication of WLAN offloading support" field, which corresponds to the first indication shown in FIG. Also, the eNB configuration update message may include a "List of WLAN" field.

  In step S121, the MME transmits an eNB configuration update confirmation response message to the eNB. The eNB configuration update acknowledgment message is used to acknowledge the eNB delivery updated information for TNL association. Table 7 illustrates an example of an eNB configuration update acknowledgment message according to an embodiment of the present invention.

<Table 7>

  Referring to Table 7, the eNB configuration update response message may include a "with indication of applying different charging rule" field, which corresponds to the second indication shown in FIG.

  FIG. 10 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 10 corresponds to the UE-specific scheme. That is, the method illustrated in FIG. 10 may be applied to a specific UE linked to an eNB.

  In step S200, the eNB transmits a first instruction of WLAN off-node support to the MME. The first instruction indicates whether the eNB supports WLAN offloading. The first indication may be sent via an initial UE message or an uplink NAS transfer message. However, the initial UE message or uplink link NAS transfer message is merely an example, and the first indication may be sent via another existing message or a newly defined message for such purpose. Can. Also, a supported WLAN ID (eg, SSID) may be sent to the MME along with a first indication of WLAN offloading support.

  In step S201, the MME transmits to the eNB a second indication as to whether a bearer can be offloaded. The second indication indicates a guideline as to whether a bearer can be offloaded from LTE to WLAN or from WLAN to LTE. More specifically, the second indication can indicate at least one of the following:

  (1) All E-RABs (E-UTRAN radio access bearers) of a specific UE may be offloaded.

  (2) Each specific E-RAB of a specific UE may or may not be offloaded.

  (3) A part of E-RAB of a specific UE may be offloaded or may not be offloaded.

  (4) All E-RABs of a specific UE can not be offloaded.

  (5) Offloading affects MME policy, eg, charging. Thus, if the second indication indicates that offloading affects the MME's policy, the eNB needs to report to the MME whether offloading will take place.

  The second indication may be sent via an initial context setup request message, or via an E-RAB setup request message, or via an E-RAB modification request message. However, the initial context setup request message, the E-RAB setup request message, or the E-RAB modification request message is merely an example, and through other existing messages or newly defined messages for such purpose. It can be sent.

  In step S202, when receiving the second instruction, the eNB applies the offloading scheme to the specific UE in response to the second instruction.

  Second, a method is described for informing a core network (e.g. MME) whether a particular UE or a particular bearer is serviced by a WLAN according to an embodiment of the present invention. After applying offloading at the wireless level in step S201 described above, the eNB can feed back to the MME as to whether or not offloading has been performed on a specific UE. More specifically, the eNB can notify the MME of detailed E-RAB to be offloaded from LTE to WLAN or from WLAN to LTE. This allows the core network to know whether a particular UE is served by WLAN. Alternatively, other dedicated signaling schemes may be possible. The eNB may trigger signaling each time the eNB notifies the MME for offloading. More specifically, the eNB may notify the MME as to whether or not offloading will take place. That is, the eNB can notify the MME to the detailed E-RAB that is offloaded from LTE to WLAN or from WLAN to LTE. Also, the eNB may inform the MME regarding the offloaded WLAN ID, which may affect the charging policy. When receiving information from the eNB, the MME may send the information to a home subscriber server (HSS) to apply the policy.

  FIG. 11 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 11 corresponds to step S200 of FIG. 10, which is implemented by the initial UE message.

  In step S210, the eNB transmits an initial UE message to the MME. The initial UE message is used to send an initial tier 3 message to the MME via the S1 interface. Table 8 illustrates an example of an initial UE message according to an embodiment of the present invention.

＜表８−２＞

<Table 8-1>

<Table 8-2>

  Referring to Table 8, the initial UE message may include an "indication of WLAN offloading support and / or with supported WLAN SSIDs" field, which corresponds to the first indication shown in FIG.

  FIG. 12 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 12 corresponds to step S200 of FIG. 10, which is realized by the uplink NAS transmission message.

  In step S220, the eNB transmits an uplink NAS transfer message to the MME. Uplink NAS transmission messages are used to carry NAS information via the S1 interface. Table 9 illustrates an example uplink link NAS transfer message according to an embodiment of the present invention.

<Table 9>

  Referring to Table 9, the Uplink NAS Transfer message may include the "indication of WLAN offloading support and / or with supported WLAN SSIDs" field, which corresponds to the first indication shown in FIG. Do.

  FIG. 13 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 13 corresponds to step S201 in FIG. 10, which is implemented by an initial context setup request message.

  In step S230, the eNB transmits an initial context setup request message to the MME. The initial context setup request message is used to request setup of the UE context. Table 10 shows an example of an initial context setup request message according to an embodiment of the present invention.

＜表１０−２＞

＜表１０−３＞

<Table 10-1>

<Table 10-2>

<Table 10-3>

  Referring to Table 10, the initial context setup request message may include an "offloadable or not" field for each E-RAB corresponding to the first indication shown in FIG. This indicates whether each specific E-RAB of the specific UE can be offloaded. Also, the initial context setup request message may include an "Offloading to WLAN" field corresponding to the first indication shown in FIG. This indicates that all E-RABs of a particular UE can be offloaded. Also, the initial context setup request message may include a "Not Offloading to WLAN" field corresponding to the first indication shown in FIG. This indicates that all E-RABs of a particular UE can not be offloaded. Also, the initial context setup request message may include an “Offloading to WLAN fits into MME policy, eg. Charging” field corresponding to the first instruction shown in FIG. This indicates that offloading affects MME's policy.

  FIG. 14 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 14 corresponds to step S201 of FIG. 10, which is implemented by an E-RAB setup request message.

  In step S240, the eNB transmits an E-RAB configuration request message to the MME. The E-RAB setup request message is used to request the eNB to allocate resources to one or more E-RABs via Uu and S1. Table 11 shows an example of an E-RAB setup request message according to an embodiment of the present invention.

<Table 11>

  Referring to Table 11, the E-RAB setup request message may include an "offloadable or not" field for each E-RAB corresponding to the first indication shown in FIG. This indicates whether each specific E-RAB of the specific UE can be offloaded. Also, the E-RAB setup request message may include an "Offloading to WLAN" field corresponding to the first instruction shown in FIG. This indicates that all E-RABs of a particular UE can be offloaded. Also, the E-RAB setup request message may include a "Not Offloading to WLAN" field corresponding to the first indication shown in FIG. This indicates that all E-RABs of a particular UE can not be offloaded. In addition, the E-RAB configuration request message may include an “Offloading to WLAN affects to MME policy, eg. Charging” field corresponding to the first instruction shown in FIG. This indicates that offloading affects the policy of MME.

  FIG. 15 shows a method for transmitting an indication for LTE / WLAN coordination according to another embodiment of the present invention. The method shown in FIG. 15 corresponds to step S201 of FIG. 10, which is implemented by an E-RAB modification request message.

  In step S240, the eNB transmits an E-RAB modification request message to the MME. The E-RAB modification request message is used by the eNB to request one or more E-RABs to modify data radio bearers and allocated resources via Uu and S1. Table 12 illustrates an example of an E-RAB modification request message according to an embodiment of the present invention.

<Table 12>

  Referring to Table 12, the E-RAB modification request message may include an "offloadable or not" field for each E-RAB corresponding to the first indication shown in FIG. This indicates whether each specific E-RAB of the specific UE can be offloaded. Also, the E-RAB modification request message may include an "Offloading to WLAN" field corresponding to the first indication shown in FIG. This indicates that all E-RABs of a particular UE can be offloaded. Also, the E-RAB modification request message may include a "Not Offloading to WLAN" field corresponding to the first indication shown in FIG. This indicates that all E-RABs of a particular UE can not be offloaded. In addition, the E-RAB modification request message may include an “Offloading to WLAN affects to MME policy, eg, charging” field corresponding to the first instruction shown in FIG. This indicates that offloading affects the policy of MME.

  FIG. 16 shows a wireless communication system in which an embodiment of the present invention is implemented.

  The eNB 800 can include a processor 810, a memory 820, and a transceiver 830. Processor 810 can be configured to implement the functions, processes, and / or methods described herein. A hierarchy of wireless interface protocols may be implemented by the processor 810. The memory 820 is coupled to the processor 810 to store various information for driving the processor 810. The transceiver 830 is connected to the processor 810 to transmit and / or receive radio signals.

  The MME (900) may comprise a processor 910, a memory 920, and a transceiver 930. Processor 910 can be configured to implement the functions, processes, and / or methods described herein. A hierarchy of wireless interface protocols may be implemented by the processor 910. The memory 920 is coupled to the processor 910 to store various information for driving the processor 910. The transceiver 930 is coupled to the processor 910 to transmit and / or receive radio signals.

  Processors 810, 910 may comprise application-specific integrated circuits (ASICs), other chipsets, logic circuits, and / or data processors. The memories 820, 920 may comprise read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. The transceivers 830, 930 may comprise baseband circuitry for processing radio frequency signals. When the embodiments are implemented in software, the techniques described above can be implemented with modules (eg, processes, functions, etc.) that perform the functions described above. The modules may be stored in memories 820, 920 and executed by processors 810, 910. The memories 820, 920 may be internal or external to the processors 810, 910 and may be coupled to the processors 810, 910 in a variety of well known ways.

  In the exemplary system described above, the method that can be implemented by the features of the present invention described above has been described based on the flowchart. For convenience, the method has been described in a series of steps or blocks, but the claimed features of the invention are not limited to the order of the steps or blocks, and certain steps may be different steps and in different order Or can occur simultaneously. In addition, one skilled in the art is not exclusive of the steps shown in the flowchart, includes other steps, or can remove one or more steps of the flowchart without affecting the scope of the present invention. You can understand that.

Claims (7)

A method in which an eNB (eNodeB) performs 3GPP LTE in a wireless communication system,
Sending first information to a mobility management entity (MME) indicating that WLAN offloading is supported ;
Receiving second information about an E-UTRAN radio access bearer (E-RAB) of a specific terminal (UE) that may be offloaded, said second information reporting whether said WLAN offloading is performed Request the eNB to
Apply the WLAN offloading to the specific terminal (UE; user equipment) based on the second information ;
Reporting that the WLAN offloading is performed to the MME . Said first information, WLAN identifier support; including (IDs identifiers), The method of claim 1. Said second information, it said that all bearers of a specific terminal (UE) can be offloading was or indicates whether not be offloading method of claim 1. The second information, the WLAN offloading instructs the Turkey affect the policy of the MME, the method according to claim 1. 5. The method of claim 4 , wherein the policy is charging. The first information, the initial UE message or uplink NAS (non-access stratum) is transmitted via the transmitting message, The method of claim 1. It said second information includes an initial context setup request message, E-RAB (E-UTRAN radio access bearer) is received through the setup request message or the E-RAB Modify Request message, The method of claim 1.

Images